The status of citizenship confers the right to participate as a full member of the political community. One might therefore expect foreign residents who acquire citizenship to become more engaged with politics. However, acquiring citizenship is a selective process. Foreign residents choose whether to apply, and states enact citizenship laws that make naturalization easier for some than for others. This suggests the alternative possibility that differences between naturalized citizens and the people who remain foreign residents reflect the factors that push some people to select into citizenship, rather than any effects of the new status. This paper evaluates these two alternatives, using longitudinal data to compare the same people over time. I present evidence suggesting that immigrants do not become more politically engaged after acquiring citizenship, but that the children of immigrants do become more engaged as citizens.